KVM: X86: Fix reserved bits check for MOV to CR3

commit a780a3ea628268b2ad0ed43d7f28d90db0ff18be upstream.

MSB of CR3 is a reserved bit if the PCIDE bit is not set in CR4.
It should be checked when PCIDE bit is not set, however commit
'd1cd3ce900441 ("KVM: MMU: check guest CR3 reserved bits based on
its physical address width")' removes the bit 63 checking
unconditionally. This patch fixes it by checking bit 63 of CR3
when PCIDE bit is not set in CR4.

Fixes: d1cd3ce900441 (KVM: MMU: check guest CR3 reserved bits based on its physical address width)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index fab073b195288dbcd266fbdd86b027757ad5093b..3111485b062157193368c62d6775f6958c4eb4bb 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4152,7 +4152,9 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt)
                                maxphyaddr = eax & 0xff;
                        else
                                maxphyaddr = 36;
-                       rsvd = rsvd_bits(maxphyaddr, 62);
+                       rsvd = rsvd_bits(maxphyaddr, 63);
+                       if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE)
+                               rsvd &= ~CR3_PCID_INVD;
                }
 
                if (new_val & rsvd)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index adac01d0181a28e2b63f11210164c42882015c7d..f46e4c5cdbb6bd6749a452f3ad8b6b56522641d1 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -836,7 +836,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
        }
 
        if (is_long_mode(vcpu) &&
-           (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 62)))
+           (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63)))
                return 1;
        else if (is_pae(vcpu) && is_paging(vcpu) &&
                   !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))